//You are given the root of a binary search tree (BST) and an integer val. 
//
// Find the node in the BST that the node's value equals val and return the subt
//ree rooted with that node. If such a node does not exist, return null. 
//
// 
// Example 1: 
//
// 
//Input: root = [4,2,7,1,3], val = 2
//Output: [2,1,3]
// 
//
// Example 2: 
//
// 
//Input: root = [4,2,7,1,3], val = 5
//Output: []
// 
//
// 
// Constraints: 
//
// 
// The number of nodes in the tree is in the range [1, 5000]. 
// 1 <= Node.val <= 107 
// root is a binary search tree. 
// 1 <= val <= 107 
// 
// Related Topics 树 
// 👍 117 👎 0


//leetcode submit region begin(Prohibit modification and deletion)
/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
class Solution {
//    public TreeNode searchBST(TreeNode root, int val) {
//        if(root == null || root.val == val){
//            return root;
//        }
//        return root.val < val ? searchBST(root.right,val) : searchBST(root.left,val);
//    }
    public TreeNode searchBST(TreeNode root, int val) {
        while(root != null && root.val != val) {
            root = root.val < val ? root.right : root.left;
        }
       return root;
    }
}
//leetcode submit region end(Prohibit modification and deletion)
